/Engine/Source/Runtime/SignalProcessing/Public/DSP/LongDelayAPF.h
InG is the filter coefficient used in the long delay all pass filter. InNumDelaySamples is the delay line length in samples. InMaxNumInternalBufferSamples is the maximum internal block size used internally.
FLongDelayAPF ( float InG, int32 InNumDelaySamples, int32 InMaxNumInternalBufferSamples )